We've had at least two days of sunshine in London and it feels like spring has sprung! Silicon Roundabout is bathed both traffic (as ever) and sunshine (new!). As our little world is transitioning from grey to yellow our thoughts have turned to color.

Print Magazine have a great feature on The 50 best color sites for designers, featuring a mix of both inspiring and practical links. There's things to help with choosing a color palette, ways to sharpen up your color theory and a variety of tools to help you refine your designs for those with color deficient vision.

In the past few months we've seen a riot of colorful cards popping up over in the Flickr pool too, and so we've gathered a few here to help spark some ideas.

This colourful collection of MiniCards is by photographer, Speedypixel. Taking a great range of action shots from motorcross to surfing, he's chosen bold graphics and colour to promote his photography. When you look at them with fresh eyes, you can see why - MiniCards might be small, but you can see his design very easily from a distance, it really makes this format pack a punch!

Crafter and online seller Lupin makes wonderful brooches and ornaments in felt. Sweet little birds, rainbows of butterflies and armfuls of flowers. She created these Postcards above, to put in with custom orders. Featuring shots of her own work they make not only a great thank you to her best customers, but a neat little tool to tempt those customers back again!

Now you can upload images for the front and back of Business Cards and MiniCards, you can really make the most of your shots. Photographer Mike Plunkett chose this colorful image (above) for the reverse of his cards, and we think it looks fantastic!

There's something about the strips of colour in Mike's cards that reminds us of the Ready Made Colour Lovers packs. Christina Anthony took the shot above, showing the Perfectly Pink pack of cards she ordered to hand out to the participants of her latest photography project. There's a wide range of Colour Lovers palettes to choose from - and you can even mix and match your own set for any of our products.

We fell in love with these MiniCards by visual artist Illusio Creative as soon as we saw them. Featuring her flowing artwork, she's added cord and beads to create beautiful bookmarks to send out to customers. Another designer who's taken advantage of the image upload for the reverse of the cards, she's created something truly unique.

Wherever you are - sunshine or showers - we hope we've given you a few ideas. As always, feel free to share your cards with us in the comments below or over on Flickr, and get your daily dose of MOO on Twitter